drivers/leds/led-class.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LED Class Core
   4  *
   5  * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
   6  * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
   7  */
   8
   9 #include <linux/ctype.h>
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/leds.h>
  15 #include <linux/list.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/timer.h>
  20 #include <uapi/linux/uleds.h>
  21 #include "leds.h"
  22
  23 static struct class *leds_class;
  24
  25 static ssize_t brightness_show(struct device *dev,
  26                 struct device_attribute *attr, char *buf)
  27 {
  28         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  29
  30         /* no lock needed for this */
  31         led_update_brightness(led_cdev);
  32
  33         return sprintf(buf, "%u\n", led_cdev->brightness);
  34 }
  35
  36 static ssize_t brightness_store(struct device *dev,
  37                 struct device_attribute *attr, const char *buf, size_t size)
  38 {
  39         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  40         unsigned long state;
  41         ssize_t ret;
  42
  43         mutex_lock(&led_cdev->led_access);
  44
  45         if (led_sysfs_is_disabled(led_cdev)) {
  46                 ret = -EBUSY;
  47                 goto unlock;
  48         }
  49
  50         ret = kstrtoul(buf, 10, &state);
  51         if (ret)
  52                 goto unlock;
  53
  54         if (state == LED_OFF)
  55                 led_trigger_remove(led_cdev);
  56         led_set_brightness(led_cdev, state);
  57         flush_work(&led_cdev->set_brightness_work);
  58
  59         ret = size;
  60 unlock:
  61         mutex_unlock(&led_cdev->led_access);
  62         return ret;
  63 }
  64 static DEVICE_ATTR_RW(brightness);
  65
  66 static ssize_t max_brightness_show(struct device *dev,
  67                 struct device_attribute *attr, char *buf)
  68 {
  69         struct led_classdev *led_cdev = dev_get_drvdata(dev);
  70
  71         return sprintf(buf, "%u\n", led_cdev->max_brightness);
  72 }
  73 static DEVICE_ATTR_RO(max_brightness);
  74
  75 #ifdef CONFIG_LEDS_TRIGGERS
  76 static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
  77 static struct attribute *led_trigger_attrs[] = {
  78         &dev_attr_trigger.attr,
  79         NULL,
  80 };
  81 static const struct attribute_group led_trigger_group = {
  82         .attrs = led_trigger_attrs,
  83 };
  84 #endif
  85
  86 static struct attribute *led_class_attrs[] = {
  87         &dev_attr_brightness.attr,
  88         &dev_attr_max_brightness.attr,
  89         NULL,
  90 };
  91
  92 static const struct attribute_group led_group = {
  93         .attrs = led_class_attrs,
  94 };
  95
  96 static const struct attribute_group *led_groups[] = {
  97         &led_group,
  98 #ifdef CONFIG_LEDS_TRIGGERS
  99         &led_trigger_group,
 100 #endif
 101         NULL,
 102 };
 103
 104 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 105 static ssize_t brightness_hw_changed_show(struct device *dev,
 106                 struct device_attribute *attr, char *buf)
 107 {
 108         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 109
 110         if (led_cdev->brightness_hw_changed == -1)
 111                 return -ENODATA;
 112
 113         return sprintf(buf, "%u\n", led_cdev->brightness_hw_changed);
 114 }
 115
 116 static DEVICE_ATTR_RO(brightness_hw_changed);
 117
 118 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 119 {
 120         struct device *dev = led_cdev->dev;
 121         int ret;
 122
 123         ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
 124         if (ret) {
 125                 dev_err(dev, "Error creating brightness_hw_changed\n");
 126                 return ret;
 127         }
 128
 129         led_cdev->brightness_hw_changed_kn =
 130                 sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
 131         if (!led_cdev->brightness_hw_changed_kn) {
 132                 dev_err(dev, "Error getting brightness_hw_changed kn\n");
 133                 device_remove_file(dev, &dev_attr_brightness_hw_changed);
 134                 return -ENXIO;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 141 {
 142         sysfs_put(led_cdev->brightness_hw_changed_kn);
 143         device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
 144 }
 145
 146 void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev,
 147                                                enum led_brightness brightness)
 148 {
 149         if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
 150                 return;
 151
 152         led_cdev->brightness_hw_changed = brightness;
 153         sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
 154 }
 155 EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
 156 #else
 157 static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
 158 {
 159         return 0;
 160 }
 161 static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
 162 {
 163 }
 164 #endif
 165
 166 /**
 167  * led_classdev_suspend - suspend an led_classdev.
 168  * @led_cdev: the led_classdev to suspend.
 169  */
 170 void led_classdev_suspend(struct led_classdev *led_cdev)
 171 {
 172         led_cdev->flags |= LED_SUSPENDED;
 173         led_set_brightness_nopm(led_cdev, 0);
 174 }
 175 EXPORT_SYMBOL_GPL(led_classdev_suspend);
 176
 177 /**
 178  * led_classdev_resume - resume an led_classdev.
 179  * @led_cdev: the led_classdev to resume.
 180  */
 181 void led_classdev_resume(struct led_classdev *led_cdev)
 182 {
 183         led_set_brightness_nopm(led_cdev, led_cdev->brightness);
 184
 185         if (led_cdev->flash_resume)
 186                 led_cdev->flash_resume(led_cdev);
 187
 188         led_cdev->flags &= ~LED_SUSPENDED;
 189 }
 190 EXPORT_SYMBOL_GPL(led_classdev_resume);
 191
 192 #ifdef CONFIG_PM_SLEEP
 193 static int led_suspend(struct device *dev)
 194 {
 195         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 196
 197         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 198                 led_classdev_suspend(led_cdev);
 199
 200         return 0;
 201 }
 202
 203 static int led_resume(struct device *dev)
 204 {
 205         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 206
 207         if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
 208                 led_classdev_resume(led_cdev);
 209
 210         return 0;
 211 }
 212 #endif
 213
 214 static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 215
 216 static int match_name(struct device *dev, const void *data)
 217 {
 218         if (!dev_name(dev))
 219                 return 0;
 220         return !strcmp(dev_name(dev), (char *)data);
 221 }
 222
 223 static int led_classdev_next_name(const char *init_name, char *name,
 224                                   size_t len)
 225 {
 226         unsigned int i = 0;
 227         int ret = 0;
 228         struct device *dev;
 229
 230         strlcpy(name, init_name, len);
 231
 232         while ((ret < len) &&
 233                (dev = class_find_device(leds_class, NULL, name, match_name))) {
 234                 put_device(dev);
 235                 ret = snprintf(name, len, "%s_%u", init_name, ++i);
 236         }
 237
 238         if (ret >= len)
 239                 return -ENOMEM;
 240
 241         return i;
 242 }
 243
 244 /**
 245  * of_led_classdev_register - register a new object of led_classdev class.
 246  *
 247  * @parent: parent of LED device
 248  * @led_cdev: the led_classdev structure for this device.
 249  * @np: DT node describing this LED
 250  */
 251 int of_led_classdev_register(struct device *parent, struct device_node *np,
 252                             struct led_classdev *led_cdev)
 253 {
 254         char name[LED_MAX_NAME_SIZE];
 255         int ret;
 256
 257         ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
 258         if (ret < 0)
 259                 return ret;
 260
 261         mutex_init(&led_cdev->led_access);
 262         mutex_lock(&led_cdev->led_access);
 263         led_cdev->dev = device_create_with_groups(leds_class, parent, 0,
 264                                 led_cdev, led_cdev->groups, "%s", name);
 265         if (IS_ERR(led_cdev->dev)) {
 266                 mutex_unlock(&led_cdev->led_access);
 267                 return PTR_ERR(led_cdev->dev);
 268         }
 269         led_cdev->dev->of_node = np;
 270
 271         if (ret)
 272                 dev_warn(parent, "Led %s renamed to %s due to name collision",
 273                                 led_cdev->name, dev_name(led_cdev->dev));
 274
 275         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
 276                 ret = led_add_brightness_hw_changed(led_cdev);
 277                 if (ret) {
 278                         device_unregister(led_cdev->dev);
 279                         mutex_unlock(&led_cdev->led_access);
 280                         return ret;
 281                 }
 282         }
 283
 284         led_cdev->work_flags = 0;
 285 #ifdef CONFIG_LEDS_TRIGGERS
 286         init_rwsem(&led_cdev->trigger_lock);
 287 #endif
 288 #ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
 289         led_cdev->brightness_hw_changed = -1;
 290 #endif
 291         /* add to the list of leds */
 292         down_write(&leds_list_lock);
 293         list_add_tail(&led_cdev->node, &leds_list);
 294         up_write(&leds_list_lock);
 295
 296         if (!led_cdev->max_brightness)
 297                 led_cdev->max_brightness = LED_FULL;
 298
 299         led_update_brightness(led_cdev);
 300
 301         led_init_core(led_cdev);
 302
 303 #ifdef CONFIG_LEDS_TRIGGERS
 304         led_trigger_set_default(led_cdev);
 305 #endif
 306
 307         mutex_unlock(&led_cdev->led_access);
 308
 309         dev_dbg(parent, "Registered led device: %s\n",
 310                         led_cdev->name);
 311
 312         return 0;
 313 }
 314 EXPORT_SYMBOL_GPL(of_led_classdev_register);
 315
 316 /**
 317  * led_classdev_unregister - unregisters a object of led_properties class.
 318  * @led_cdev: the led device to unregister
 319  *
 320  * Unregisters a previously registered via led_classdev_register object.
 321  */
 322 void led_classdev_unregister(struct led_classdev *led_cdev)
 323 {
 324 #ifdef CONFIG_LEDS_TRIGGERS
 325         down_write(&led_cdev->trigger_lock);
 326         if (led_cdev->trigger)
 327                 led_trigger_set(led_cdev, NULL);
 328         up_write(&led_cdev->trigger_lock);
 329 #endif
 330
 331         led_cdev->flags |= LED_UNREGISTERING;
 332
 333         /* Stop blinking */
 334         led_stop_software_blink(led_cdev);
 335
 336         led_set_brightness(led_cdev, LED_OFF);
 337
 338         flush_work(&led_cdev->set_brightness_work);
 339
 340         if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
 341                 led_remove_brightness_hw_changed(led_cdev);
 342
 343         device_unregister(led_cdev->dev);
 344
 345         down_write(&leds_list_lock);
 346         list_del(&led_cdev->node);
 347         up_write(&leds_list_lock);
 348
 349         mutex_destroy(&led_cdev->led_access);
 350 }
 351 EXPORT_SYMBOL_GPL(led_classdev_unregister);
 352
 353 static void devm_led_classdev_release(struct device *dev, void *res)
 354 {
 355         led_classdev_unregister(*(struct led_classdev **)res);
 356 }
 357
 358 /**
 359  * devm_of_led_classdev_register - resource managed led_classdev_register()
 360  *
 361  * @parent: parent of LED device
 362  * @led_cdev: the led_classdev structure for this device.
 363  */
 364 int devm_of_led_classdev_register(struct device *parent,
 365                                   struct device_node *np,
 366                                   struct led_classdev *led_cdev)
 367 {
 368         struct led_classdev **dr;
 369         int rc;
 370
 371         dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
 372         if (!dr)
 373                 return -ENOMEM;
 374
 375         rc = of_led_classdev_register(parent, np, led_cdev);
 376         if (rc) {
 377                 devres_free(dr);
 378                 return rc;
 379         }
 380
 381         *dr = led_cdev;
 382         devres_add(parent, dr);
 383
 384         return 0;
 385 }
 386 EXPORT_SYMBOL_GPL(devm_of_led_classdev_register);
 387
 388 static int devm_led_classdev_match(struct device *dev, void *res, void *data)
 389 {
 390         struct led_cdev **p = res;
 391
 392         if (WARN_ON(!p || !*p))
 393                 return 0;
 394
 395         return *p == data;
 396 }
 397
 398 /**
 399  * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 400  * @parent: The device to unregister.
 401  * @led_cdev: the led_classdev structure for this device.
 402  */
 403 void devm_led_classdev_unregister(struct device *dev,
 404                                   struct led_classdev *led_cdev)
 405 {
 406         WARN_ON(devres_release(dev,
 407                                devm_led_classdev_release,
 408                                devm_led_classdev_match, led_cdev));
 409 }
 410 EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);
 411
 412 static int __init leds_init(void)
 413 {
 414         leds_class = class_create(THIS_MODULE, "leds");
 415         if (IS_ERR(leds_class))
 416                 return PTR_ERR(leds_class);
 417         leds_class->pm = &leds_class_dev_pm_ops;
 418         leds_class->dev_groups = led_groups;
 419         return 0;
 420 }
 421
 422 static void __exit leds_exit(void)
 423 {
 424         class_destroy(leds_class);
 425 }
 426
 427 subsys_initcall(leds_init);
 428 module_exit(leds_exit);
 429
 430 MODULE_AUTHOR("John Lenz, Richard Purdie");
 431 MODULE_LICENSE("GPL");
 432 MODULE_DESCRIPTION("LED Class Interface");